scholarly journals Microbial metabolism of pyridinium compounds. Radioisotope studies of the metabolic fate of 4-carboxy-1-methylpyridinium chloride

1972 ◽  
Vol 128 (3) ◽  
pp. 561-568 ◽  
Author(s):  
K. A. Wright ◽  
R. B. Cain
Keyword(s):  
Microbial Metabolism ◽  
Heterocyclic Ring ◽  
Ring Cleavage ◽  
Carboxyl Group ◽  
Metabolic Fate ◽  
Methyl Group ◽  
End Products ◽  
Pyridinium Compounds

Extracts of Achromobacter D formed CO2, methylamine, succinate and formate as metabolic end-products from N-methylisonicotinic acid (4-carboxy-1-methylpyridinium chloride). The origin of the CO2 in the 4-carboxyl group and of the methylamine in the N-methyl group of N-methylisonicotinate was demonstrated with carboxyl-14C- and N-Me-14C-labelled substrates respectively. The carbon skeletons of formate and succinate were shown to arise from the C-2 and the C-3–C-6 atoms of the heterocyclic ring respectively by using N-methyl[2,3-14C2]isonicotinate. This result is consistent with ring cleavage by the organism between C-2 and C-3.

scholarly journals Microbial metabolism of pyridinium compounds. Metabolism of 4-carboxy-1-methylpyridinium chloride, a photolytic product of paraquat

1972 ◽  
Vol 128 (3) ◽  
pp. 543-559 ◽  
Author(s):  
K. A. Wright ◽  
R. B. Cain
Keyword(s):  
Sole Carbon Source ◽  
Heterocyclic Ring ◽  
Time Sequence ◽  
Garden Soil ◽  
Succinic Semialdehyde ◽  
Succinic Semialdehyde Dehydrogenase ◽  
Methyl Group ◽  
Semialdehyde Dehydrogenase ◽  
End Products ◽  
Pyridinium Compounds

1. A bacterium, Achromobacter D, isolated from garden soil by elective culture, utilized N-methylisonicotinic acid (4-carboxy-1-methylpyridinium chloride) as sole carbon source. 2. Extracts of N-methylisonicotinate-grown cells oxidized this substrate only after supplementation with a source of nicotinamide nucleotides and then consumed 1 mol of O2 and released 1 mol of CO2/mol of N-methylisonicotinate supplied. 3. The N-methyl group of the substrate was released as methylamine whereas the five C atoms of the pyridine ring were accounted for as succinate and formate. The CO2 evolved by extracts was believed to derive from the carboxyl group on C-4 of the heterocyclic ring. 4. The immediate precursor of the succinate end-product was succinic semialdehyde; the inducible nature of succinic semialdehyde dehydrogenase in N-methylisonicotinate-grown cells supported this finding. 5. There was no evidence for monohydroxylation of the ring, but the time sequence of the appearance of the end-products indicated that the oxygen-requiring, NADH-requiring and decarboxylation steps clearly preceded the formation of methylamine and succinate. 6. The results are consistent with the oxidative cleavage of a partially reduced heterocyclic ring followed by several hydrolytic and dehydrogenase steps resulting in the appearance of the end-products.

Methanogenesis from Acetate by Methanosarcina barkeri: Catalysis of Acetate Formation from Methyl Iodide, CO2 , and H2 by the Enzyme System Involved

1987 ◽  
Vol 42 (4) ◽  
pp. 360-372 ◽  
Author(s):  
Kerstin Laufer ◽  
Bernhard Eikmanns ◽  
Ursula Frimmer ◽  
Rudolf K. Thauer
Keyword(s):  
Methyl Iodide ◽  
Condensation Reaction ◽  
Methyl Chloride ◽  
Methanosarcina Barkeri ◽  
Carboxyl Group ◽  
Atpase Inhibitor ◽  
Methyl Group ◽  
Proton Potential ◽  
Acetate Formation ◽  
Reducing Equivalents

Cell suspensions of Methanosarcina barkeri grown on acetate catalyze the formation of methane and CO2 from acetate as well as an isotopic exchange between the carboxyl group of acetate and CO2. Here we report that these cells also mediate the synthesis of acetate from methyl iodide, CO2, and reducing equivalents (H2 or CO), the methyl group of acetate being derived from methyl iodide and the carboxyl group from CO2. Methyl chloride and methyltosylate but not methanol can substitute for methyl iodide in this reaction. Acetate formation from methyl iodide, CO2, and reducing equivalents is coupled with the phosphorylation of ADP. Evidence is pres­ented that methyl iodide is incorporated into the methyl group of acetate via a methyl corrinoid intermediate (deduced from inhibition experiments with propyl iodide) and that CO2 is assimi­lated into the carboxyl group via a C1 intermediate which does not exchange with free formate or free CO. The effects of protonophores, of the proton-translocating ATPase inhibitor N.N′-di- cyclohexylcarbodiimide, and of arsenate on acetate formation are interpreted to indicate that the reduction of CO2 to the oxidation level of the carboxyl group of acetate requires the presence of an electrochemical proton potential and that acetyl-CoA or acetyl-phosphate rather than free acetate is the immediate product of the condensation reaction. These results are discussed with respect to the mechanism of methanogenesis from acetate.

scholarly journals Synthesis of Novel 1,2,3-Triazole-Dihydropyrimidinone Hybrids Using Multicomponent 1,3-Dipolar Cycloaddition (Click)–Biginelli Reactions: Anticancer Activity

Synlett ◽  
2020 ◽  
Vol 31 (06) ◽  
pp. 615-621
Author(s):  
Elisabete P. Carreiro ◽  
Ana M. Sena ◽  
Adrián Puerta ◽  
José M. Padrón ◽  
Anthony J. Burke
Keyword(s):  
Breast Cancer ◽  
Lung Cancer ◽  
Heterocyclic Ring ◽  
Small Cell ◽  
Dipolar Cycloaddition ◽  
Cancer Cervix ◽  
Small Cell Lung ◽  
Methyl Group ◽  
Cancer Breast ◽  
Biginelli Reactions

In this work, 21 novel (1,4-disubstituted 1,2,3-triazole)-dihydropyrimidinone (1,2,3-trzl-DHPM) type hybrids were synthesized and characterized. These were divided into two types: hybrids A (5 in total) containing the dihydropyrimidinone heterocyclic ring decorated with a 1,4-disubstituted 1,2,3-triazole in the C-5 position [these compounds were accessed by a multicomponent copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) (or click)–Biginelli reactions with satisfactory yields (39–57%)] and hybrids B (16 in total) containing two 1,2,3-triazole units in the C-5 and C-6 methyl position of the DHPM. Hybrids B were synthesized via functionalization of the C-6 methyl group of hybrids A, a multistep sequence of reactions was used that included bromination, azidation, and a CuAAC. Hybrids B were obtained in very good to excellent yields (up to 99%). Some hybrids A and B were evaluated for their antiproliferative activity against different cancer cell lines that included A549 and SW1573 (non-small-cell lung), HBL-100 and T-47D (breast), HeLa (cervix) and WiDr (colon). Three of these hybrids were potent cell proliferation inhibitors of non-small-cell lung cancer, cervix cancer, breast cancer, and colon cancer.

Effects of B vitamins and methyl group donors on milk production, milk composition and blood biochemistry in dairy cows

2002 ◽  
Vol 2002 ◽  
pp. 196-196
Author(s):  
S.E Richards ◽  
S Hicklin ◽  
T Lord ◽  
A Nickson ◽  
J Long ◽  
...  
Keyword(s):  
Milk Yield ◽  
Milk Composition ◽  
Metabolic Fate ◽  
Dry Period ◽  
Very Low Density Lipoproteins ◽  
Methyl Group ◽  
Fat Reserves ◽  
Esterified Fatty Acids ◽  
Pregnancy And Lactation ◽  
Tag Accumulation

Recent reviews highlight the importance of the liver in the coordination of nutrient fluxes in support of pregnancy and lactation (e.g. Drackley et al., 2001). Mobilisation of body fat reserves in the late dry period and early lactation leads to an increase in uptake of non-esterified fatty acids (NEFA) by the liver. Their metabolic fate is either oxidation or esterification into triacylglycerides (TAG) that are either exported in very low density lipoproteins (VLDL) or accumulated within liver cells. Recent evidence indicates that TAG accumulation impairs ureagenic and gluconeogenic capacity of the liver, with consequent reductions in feed intake and milk yield, increased incidence of disease and decreased reproductive performance (Overton and Piepenbrink, 1999).LiFTTM (NuTec Ltd.) is a proprietary mixture of B-group vitamins and methyl group donors (rumen protected choline, niacin, vitamin B12, biotin, folic acid and thiamine) designed to reduce the accumulation of TAG in the liver and accelerate VLDL export. The objective of this experiment was to evaluate the effect of LiFT on milk yield and composition and concentrations of metabolites in blood.

THE ANAEROBIC DISSIMILATION OF D-GLUCOSE-1-C14, D-ARABINOSE-1-C14, AND L-ARABINOSE-1-C14 BY AEROBACTER AEROGENES

1954 ◽  
Vol 32 (1) ◽  
pp. 147-153 ◽  
Author(s):  
A. C. Neish ◽  
F. J. Simpson
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Carboxyl Groups ◽  
Methyl Groups ◽  
Carboxyl Group ◽  
Complete Conversion ◽  
Aerobacter Aerogenes ◽  
Methyl Group ◽  
Ethanol Acetic Acid

D-Glucose-1-C14, D-arabinose-1-C14, and L-arabinose-1-C14 were dissimilated anaerobically by Aerobacter aerogenes. The major products (2,3-butanediol, ethanol, acetic acid, lactic acid, formic acid, and carbon dioxide) were isolated and the location of C14 determined. The products from glucose were all labeled, mainly in the methyl groups, in agreement with the hypothesis that they were derived from methyl-labeled pyruvate formed by the reactions of the classical Embden–Meyerhof scheme for glycolysis. The products from both pentoses appeared to have been formed from pyruvate labeled in both the methyl and carboxyl groups with twice as much C14 in the methyl group as in the carboxyl group. This result may be explained quantitatively by a hypothesis assuming complete conversion of pentose to triose via a heptulose.

Domino Reactions of Chromones with Heterocyclic Enamines

Synlett ◽  
2021 ◽  
Author(s):  
Peter Langer
Keyword(s):  
Carbon Atom ◽  
Carbonyl Group ◽  
Functional Groups ◽  
Conjugate Addition ◽  
Heterocyclic Ring ◽  
Ring Cleavage ◽  
Domino Reactions ◽  
Chromone Derivatives ◽  
Convenient Synthesis ◽  
Heterocyclic Enamines

AbstractDomino reactions of heterocyclic enamines with chromone derivatives provides a convenient synthesis of a great variety of annulated heterocyclic ring systems. The course of the reaction depends on the type of substituent located at position 3 of the chromone. Reactions of 3-unsubstituted chromones, 3-nitrochromones, and 3-halochromones proceed by conjugate addition of the carbon atom of the enamine to carbon C-2 of the chromone, ring cleavage, and recyclization via the chromone carbonyl group. In the case of 3-formylchromes, 3-dichloroacetylchromone, 3-perfluoroalkanoylthiochromones, 3-(2-fluorobenzoyl)chromones, and 3-methoxalylchromones the final cyclization proceeds via the carbonyl group located outside the chromone moiety. The functional groups located at the carbonyl group at position 3 of the chromone allow for further synthetic transformations including additional ring closures.Contents1 Introduction2 3-Unsubstituted Chromones3 3-Nitrochromones4 3-Formylchromes5 3-Dichloroacetylchromone6 3-Perfluoroalkanoylthiochromones7 3-Methoxalylchromones8 3-(2-Fluorobenzoyl)chromones9 3-Halochromones10 Chromone-3-carboxylic Acids11 Conclusions

THE ANAEROBIC DISSIMILATION OF D-GLUCOSE-1-C14, D-ARABINOSE-1-C14, AND L-ARABINOSE-1-C14 BY AEROBACTER AEROGENES

1954 ◽  
Vol 32 (3) ◽  
pp. 147-153 ◽  
Author(s):  
A. C. Neish ◽  
F. J. Simpson
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Carboxyl Groups ◽  
Methyl Groups ◽  
Carboxyl Group ◽  
Complete Conversion ◽  
Aerobacter Aerogenes ◽  
Methyl Group ◽  
Ethanol Acetic Acid

D-Glucose-1-C14, D-arabinose-1-C14, and L-arabinose-1-C14 were dissimilated anaerobically by Aerobacter aerogenes. The major products (2,3-butanediol, ethanol, acetic acid, lactic acid, formic acid, and carbon dioxide) were isolated and the location of C14 determined. The products from glucose were all labeled, mainly in the methyl groups, in agreement with the hypothesis that they were derived from methyl-labeled pyruvate formed by the reactions of the classical Embden–Meyerhof scheme for glycolysis. The products from both pentoses appeared to have been formed from pyruvate labeled in both the methyl and carboxyl groups with twice as much C14 in the methyl group as in the carboxyl group. This result may be explained quantitatively by a hypothesis assuming complete conversion of pentose to triose via a heptulose.

scholarly journals Ring-Cleaving Dioxygenases with a Cupin Fold

2012 ◽  
Vol 78 (8) ◽  
pp. 2505-2514 ◽  
Author(s):  
Susanne Fetzner
Keyword(s):  
Electron Transfer ◽  
Metal Ion ◽  
Direct Electron Transfer ◽  
Heterocyclic Ring ◽  
Divalent Metal ◽  
Ring Cleavage ◽  
Type I ◽  
Divalent Metal Ions ◽  
Canonical Type ◽  
Extradiol Dioxygenases

ABSTRACTRing-cleaving dioxygenases catalyze key reactions in the aerobic microbial degradation of aromatic compounds. Many pathways converge to catecholic intermediates, which are subject toorthoormetacleavage by intradiol or extradiol dioxygenases, respectively. However, a number of degradation pathways proceed via noncatecholic hydroxy-substituted aromatic carboxylic acids like gentisate, salicylate, 1-hydroxy-2-naphthoate, or aminohydroxybenzoates. The ring-cleaving dioxygenases active toward these compounds belong to the cupin superfamily, which is characterized by a six-stranded β-barrel fold and conserved amino acid motifs that provide the 3His or 2- or 3His-1Glu ligand environment of a divalent metal ion. Most cupin-type ring cleavage dioxygenases use an FeIIcenter for catalysis, and the proposed mechanism is very similar to that of the canonical (type I) extradiol dioxygenases. The metal ion is presumed to act as an electron conduit for single electron transfer from the metal-bound substrate anion to O2, resulting in activation of both substrates to radical species. The family of cupin-type dioxygenases also involves quercetinase (flavonol 2,4-dioxygenase), which opens up two C-C bonds of the heterocyclic ring of quercetin, a wide-spread plant flavonol. Remarkably, bacterial quercetinases are capable of using different divalent metal ions for catalysis, suggesting that the redox properties of the metal are relatively unimportant for the catalytic reaction. The major role of the active-site metal ion could be to correctly position the substrate and to stabilize transition states and intermediates rather than to mediate electron transfer. The tentative hypothesis that quercetinase catalysis involves direct electron transfer from metal-bound flavonolate to O2is supported by model chemistry.

The conformational properties of the gangliosides GM2 and GM1 based on 1H and,13C nuclear magnetic resonance studies

1984 ◽  
Vol 62 (6) ◽  
pp. 1034-1045 ◽  
Author(s):  
Subramaniam Sabesan ◽  
Klaus Bock ◽  
Raymond U. Lemieux
Keyword(s):  
Biological Properties ◽  
Carboxyl Group ◽  
Methyl Group ◽  
Acetylneuraminic Acid ◽  
Conformational Preferences ◽  
13C Nuclear Magnetic Resonance ◽  
Chemical Shift Data ◽  
Nuclear Overhauser ◽  
Shift Data ◽  
C Nmr

A comparison of the 1H and 13C nmr parameters for the disaccharide derivatives βDGal(1→ 4)βDGlcO(CH2)8COOCH3 (1), βDGalNAc(1 → 4)βDGalO(CH2)8COOCH3 (2), and βDGal(1 → 3)βDGalNAcO(CH2)2CH3 (3) allowed assignments of the signals observed for the asialo-GM2- and asialo-GM1-related synthetic haptens, βDGalNAc(1 → 4)βDGal(1→4)βDGlcO(CH2)8COOCH3 (4) and βDGal(1 → 3)βDGalNAc(1 → 4)βDGal(1 → 4)βDGlcO(CH2)8COOCH3 (5). 1H nuclear Overhauser enhancement studies confirmed the conformational preferences for 2 and 3 predicted by HSEA calculation. Comparison of the 1H and 13C spectra indicate that these preferences and that previously known for the lactoside (1) are closely maintained in the haptens 4 and 5. HSEA calculation indicates that the methyl group of methyl N-acetyl-α-D-neuraminic acid (10) prefers the orientation wherein the carboxyl group is near anti-periplanar to the methyl group. However, this orientation was not confirmed by saturation of the methyl group since no enhancement of either Ha-3 or He-3 was observed. On the other hand, saturation of Ha-3c of the αDNeuAc unit of the GM1-related pentasaccharide, βDGal(1 → 3)βDGalNAc(1 → 4)[αDNeuAc(2 → 3)]βDGal(1→4)α,βDGlc, caused strong enhancement of the signal for the aglyconic hydrogen, H-3bof the βDGal(1→4) unit. This observation, along with those of other nuclear Overhauser experiments, established that this pentasaccharide has the carboxyl group anti-periplanar to C-3b. Furthermore, the C-7c to C-9c chain of the αDNeuAc unit adopts nearly the same conformation for the compound in aqueous solution as exists for N-acetylneuraminic acid in the crystalline state. The HSEA calculation indicates important attractive interaction between this chain and the βDGalNAc unit of the aglycon. These conlcusions were extended to the GM2 and GM1 gangliosides by the comparison of chemical shift data. In these compounds, the carboxyl group projects over the hydrophobic α-side of the βDGalNAc unit and the polar OH-4c, NAc-5c, OH-7c groups project over the hydrophobic β-side of the lactose unit. Comments are made on the possible bearing of these topographical features on certain biological properties of gangliosides.

Specificity of the transport system for neutral amino acids in the hamster intestine

1962 ◽  
Vol 202 (5) ◽  
pp. 919-925 ◽  
Author(s):  
Edmund C. C. Lin ◽  
Hiroshi Hagihira ◽  
T. Hastings Wilson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transport System ◽  
Side Chain ◽  
Carboxyl Group ◽  
Amino Group ◽  
Methyl Group ◽  
Neutral Amino Acids ◽  
Active Transport System ◽  
Everted Sacs

The specificity of the active transport system for neutral amino acids has been studied with everted sacs of hamster intestine. Amino acids with modifications or replacements of the carboxyl, amino, or α-hydrogen groups were poorly transported and were poor inhibitors of the transport of other l-amino acids. The carboxyl group must remain free, the amino group must not be in the tertiary or quaternary state, and the α-hydrogen can not be replaced by a methyl group without serious effect on the transport rate. It was concluded that the l-amino acids were distinguished from the d-isomers by the interaction of the carrier with the carboxyl group, the amino group, and the α-hydrogen. The side chain of the amino acid must be nonpolar but there is relatively little restriction on its structure.

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